scholarly journals Effects of surface current–wind interaction in an eddy-rich general ocean circulation simulation of the Baltic Sea

Ocean Science ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 977-986 ◽  
Author(s):  
Heiner Dietze ◽  
Ulrike Löptien
Keyword(s):  
Baltic Sea ◽  
Ocean Circulation ◽  
Surface Waters ◽  
Algal Blooms ◽  
Circulation Model ◽  
Transport Processes ◽  
Surface Currents ◽  
Wind Effects ◽  
The Baltic Sea ◽  
The Baltic

Abstract. Deoxygenation in the Baltic Sea endangers fish yields and favours noxious algal blooms. Yet, vertical transport processes ventilating the oxygen-deprived waters at depth and replenishing nutrient-deprived surface waters (thereby fuelling export of organic matter to depth) are not comprehensively understood. Here, we investigate the effects of the interaction between surface currents and winds on upwelling in an eddy-rich general ocean circulation model of the Baltic Sea. Contrary to expectations we find that accounting for current–wind effects inhibits the overall vertical exchange between oxygenated surface waters and oxygen-deprived water at depth. At major upwelling sites, however (e.g. off the southern coast of Sweden and Finland) the reverse holds: the interaction between topographically steered surface currents with winds blowing over the sea results in a climatological sea surface temperature cooling of 0.5 K. This implies that current–wind effects drive substantial local upwelling of cold and nutrient-replete waters.

scholarly journals Effects of surface current/wind interaction in an eddy-rich general ocean circulation simulation of the Baltic Sea

2016 ◽  
Author(s):  
H. Dietze ◽  
U. Löptien
Keyword(s):  
Baltic Sea ◽  
Ocean Circulation ◽  
Surface Waters ◽  
Algal Blooms ◽  
Circulation Model ◽  
Transport Processes ◽  
Surface Currents ◽  
Wind Effects ◽  
The Baltic Sea ◽  
The Baltic

Abstract. Deoxygenation in the Baltic Sea endangers fish yields and favours noxious algal blooms. Yet, vertical transport processes ventilating the oxygen-deprived waters at depth and replenishing nutrient-deprived surface waters (thereby fuelling export of organic matter to depth), are not comprehensively understood. Here, we investigate the effects of the interaction between surface currents and winds (also referred to as eddy/wind effects) on upwelling in an eddy-rich general ocean circulation model of the Baltic Sea. Contrary to expectations we find that accounting for current/wind effects does inhibit the overall vertical exchange between oxygenated surface waters and oxygen-deprived water at depth. At major upwelling sites, however, as e.g. off the south coast of Sweden and Finland, the reverse holds: the interaction between topographically steered surface currents with winds blowing over the sea results in a climatological sea surface temperature cooling of 0.5 K. This implies that current/wind effects drive substantial local upwelling of cold and nutrient-replete waters.

Model based assessment of drift and fate of marine micro plastics in the Baltic Sea

2021 ◽  
Author(s):  
Jens Murawski ◽  
Jun She ◽  
Vilnis Frishfelds
Keyword(s):  
Baltic Sea ◽  
Ocean Circulation ◽  
Particle Surface ◽  
Circulation Model ◽  
Plastic Pollution ◽  
The Baltic Sea ◽  
Sea Transport ◽  
Biofilm Growth ◽  
Model Based ◽  
The Baltic

<p>Marine micro plastic is a growing problem, because of its ability to accumulate in the environment. Reliable data of drift patterns and accumulation zones are required to estimate environmental impacts on natural protected areas, spawning areas and vulnerable habitats. H2020 project CLAIM (Cleaning Litter by developing and Applying Innovative Methods) uses model based assessments to improve the knowledge on marine pathways, sources and sinks of land emitted plastic pollution. The assessment follows a systematic approach, to derive reliable emission values for coastal sources, and to model drift and deposition pattern of micro plastics from multiple sources: car tyres, cosmetic products. A 3D modelling tool has been developed, that includes all relevant key processes, i.e. currents and wave induced transport, biofilm growth on the particle surface, sinking and sedimentation. Core engine is the HBM ocean circulation model, which has been set-up for the Baltic Sea in high resolution of 900m. Multi-years-studies (2013-2019) were performed to evaluate seasonal drift pattern and accumulation zones. Highest micro plastic concentrations were found in coastal waters, near major release locations, but transport related offshore pattern can be found as well. These follow the major pathways of deeper sea transport, but are controlled by the seasonal dynamic of biofilm growth and sinking. We introduce the model and all relevant key processes. Seasonal drift pattern are discusses in detail. Validation results in the Gulf of Riga and the Gulf of Finland provide an overview of the quality of the model to predict the distribution of micro plastics. The study includes the assessment of mitigation scenarios, of 30% micro plastic load reductions. The impacts on the ocean levels of micro plastic concentrations are studied in detail.  </p><p> </p><p> </p>

scholarly journals Nemo-Nordic 2.0: Operational marine forecast model for the Baltic Sea

2021 ◽  
Author(s):  
Tuomas Kärnä ◽  
Patrik Ljungemyr ◽  
Saeed Falahat ◽  
Ida Ringgaard ◽  
Lars Axell ◽  
...  
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Sea Level ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Forecast Model ◽  
The Baltic Sea ◽  
Baltic Basin ◽  
The North ◽  
The Baltic

Abstract. This paper describes Nemo-Nordic 2.0, an operational marine forecast model for the Baltic Sea. The model is based on the NEMO (Nucleus for European Modelling of the Ocean) circulation model and the previous Nemo-Nordic 1.0 configuration by Hordoir et al. [Geosci. Model Dev., 12, 363–386, 2019]. The most notable updates include the switch from NEMO version 3.6 to 4.0, updated model bathymetry and revised bottom friction formulation. The model domain covers the Baltic and the North Seas with approximately 1 nautical mile resolution. Vertical grid resolution has been increased from 3 to 1 m in the surface layer. In addition, the numerical solver configuration has been revised to reduce artificial mixing to improve the representation of inflow events. Sea-ice is modeled with the SI3 model instead of LIM3. The model is validated against sea level, water temperature and salinity observations, as well as Baltic Sea ice chart data for a two-year hindcast simulation. Sea level root mean square deviation (RMSD) is typically within 10 cm throughout the Baltic basin. Seasonal sea surface temperature variation is well captured, although the model exhibits a negative bias of approximately −0.5 °C. Salinity RMSD is typically below 1.5 g/kg. The model captures the 2014 Major Baltic Inflow event and its propagation to the Gotland Deep. The skill analysis demonstrates that Nemo-Nordic 2.0 can reproduce the hydrographic features of the Baltic Sea.

scholarly journals Nemo-Nordic 2.0: operational marine forecast model for the Baltic Sea

2021 ◽  
Vol 14 (9) ◽  
pp. 5731-5749
Author(s):  
Tuomas Kärnä ◽  
Patrik Ljungemyr ◽  
Saeed Falahat ◽  
Ida Ringgaard ◽  
Lars Axell ◽  
...  
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Water Temperature ◽  
Sea Level ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Sea Surface ◽  
Model Assessment ◽  
The Baltic Sea ◽  
The Baltic

Abstract. This paper describes Nemo-Nordic 2.0, an operational marine model for the Baltic Sea. The model is used for both near-real-time forecasts and hindcast purposes. It provides estimates of sea surface height, water temperature, salinity, and velocity, as well as sea ice concentration and thickness. The model is based on the NEMO (Nucleus for European Modelling of the Ocean) circulation model and the previous Nemo-Nordic 1.0 configuration by Hordoir et al. (2019). The most notable updates include the switch from NEMO version 3.6 to 4.0, updated model bathymetry, and revised bottom friction formulation. The model domain covers the Baltic Sea and the North Sea with approximately 1 nmi resolution. Vertical grid resolution has been increased from 3 to 1 m in the surface layer. In addition, the numerical solver configuration has been revised to reduce artificial mixing to improve the representation of inflow events. Sea ice is modeled with the SI3 model instead of LIM3. The model is validated against sea level, water temperature, and salinity observations, as well as Baltic Sea ice chart data for a 2-year hindcast simulation (October 2014 to September 2016). Sea level root mean square deviation (RMSD) is typically within 10 cm throughout the Baltic basin. Seasonal sea surface temperature variation is well captured, although the model exhibits a negative bias of approximately −0.5 ∘C. Salinity RMSD is typically below 1.5 g kg−1. The model captures the 2014 major Baltic inflow event and its propagation to the Gotland Deep. The model assessment demonstrates that Nemo-Nordic 2.0 can reproduce the hydrographic features of the Baltic Sea.

Fate and dynamic of marine micro plastics in the Baltic Sea

2020 ◽  
Author(s):  
Jens Murawski ◽  
Jun She
Keyword(s):  
Baltic Sea ◽  
Ocean Circulation ◽  
Sea Water ◽  
Circulation Model ◽  
Cosmetic Products ◽  
Ocean Circulation Model ◽  
The Baltic Sea ◽  
Innovative Methods ◽  
The Baltic ◽  
Tyre Wear

<p>The fate of micro plastic litter (<5mm) in the marine environment is still largely unknown. H2020 project CLAIM (Cleaning Litter by developing and Applying Innovative Methods) uses model based assessments to improve our knowledge on the micro plastic sources, sinks and pathways. A systematic approach for assessing the sources and pathways of land emitted microplastics was developed and applied for two types of micro plastic from car tyres and cosmetic products. After entering the sea, micro plastic pollutants are affected by transport, biofouling, sinking and sedimentation. A 3D modelling tool has been developed by including these processes. Multi-years-studies (2013-2018) were performed to evaluate seasonal drift pattern and accumulation zones. DMI’s high resolution ocean circulation model HBM, in 900m resolution for the entire Baltic Sea serves as the modelling platform for the assessments. It was found that the fate of micro plastics at sea depends largely on transport and the sinking processes, including biofouling. Tyre wear is heavier than sea water and is accumulating in the deeper parts of the Baltic Sea, whereas micro plastics from cosmetic products are lighter than sea water and are floating near the surface, until biofouling has increased their density sufficiently enough. Key processes that determine the fate micro plastics at sea are introduced and the results of the multi-year study: drift pattern and accumulation zones are presented.</p>

scholarly journals Nitrate source identification in the Baltic Sea using its isotopic ratios in combination with a Bayesian isotope mixing model

2014 ◽  
Vol 11 (17) ◽  
pp. 4913-4924 ◽  
Author(s):  
F. Korth ◽  
B. Deutsch ◽  
C. Frey ◽  
C. Moros ◽  
M. Voss
Keyword(s):  
Atmospheric Deposition ◽  
Baltic Sea ◽  
Surface Waters ◽  
N2 Fixation ◽  
Source Identification ◽  
Agricultural Land ◽  
Mixing Model ◽  
The Baltic Sea ◽  
Bayesian Isotope Mixing Model ◽  
The Baltic

Abstract. Nitrate (NO3−) is the major nutrient responsible for coastal eutrophication worldwide and its production is related to intensive food production and fossil-fuel combustion. In the Baltic Sea NO3− inputs have increased 4-fold over recent decades and now remain constantly high. NO3− source identification is therefore an important consideration in environmental management strategies. In this study focusing on the Baltic Sea, we used a method to estimate the proportional contributions of NO3− from atmospheric deposition, N2 fixation, and runoff from pristine soils as well as from agricultural land. Our approach combines data on the dual isotopes of NO3− (δ15N-NO3− and δ18O-NO3−) in winter surface waters with a Bayesian isotope mixing model (Stable Isotope Analysis in R, SIAR). Based on data gathered from 47 sampling locations over the entire Baltic Sea, the majority of the NO3− in the southern Baltic was shown to derive from runoff from agricultural land (33–100%), whereas in the northern Baltic, i.e. the Gulf of Bothnia, NO3− originates from nitrification in pristine soils (34–100%). Atmospheric deposition accounts for only a small percentage of NO3− levels in the Baltic Sea, except for contributions from northern rivers, where the levels of atmospheric NO3− are higher. An additional important source in the central Baltic Sea is N2 fixation by diazotrophs, which contributes 49–65% of the overall NO3− pool at this site. The results obtained with this method are in good agreement with source estimates based upon δ15N values in sediments and a three-dimensional ecosystem model, ERGOM. We suggest that this approach can be easily modified to determine NO3− sources in other marginal seas or larger near-coastal areas where NO3− is abundant in winter surface waters when fractionation processes are minor.

scholarly journals Dissolved iron (II) in the Baltic Sea surface water and implications for cyanobacterial bloom development

2009 ◽  
Vol 6 (2) ◽  
pp. 3803-3850 ◽  
Author(s):  
E. Breitbarth ◽  
J. Gelting ◽  
J. Walve ◽  
L. J. Hoffmann ◽  
D. R. Turner ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Surface Waters ◽  
Cyanobacterial Bloom ◽  
Euphotic Zone ◽  
Strong Wind ◽  
Ferrous Ions ◽  
The Baltic Sea ◽  
High Concentrations ◽  
Wind Events ◽  
The Baltic

Abstract. Iron chemistry measurements were conducted during summer 2007 at two distinct locations in the Baltic Sea (Gotland Deep and Landsort Deep) to evaluate the role of iron for cyanobacterial bloom development in these estuarine waters. Depth profiles of Fe(II) were measured by chemiluminescent flow injection analysis (CL-FIA) and reveal several origins of Fe(II) to the water column. Photoreduction of Fe(III)-complexes and deposition by rain are main sources of Fe(II) (up to 0.9 nmol L−1) in light penetrated surface waters. Indication for organic Fe(II) complexation resulting in prolonged residence times in oxygenated water was observed. Surface dwelling heterocystous cyanobacteria where mainly responsible for Fe(II) consumption in comparison to other phytoplankton. The significant Fe(II) concentrations in surface waters apparently play a major role in cyanobacterial bloom development in the Baltic Sea and are a major contributor to the Fe requirements of diazotrophs. Second, Fe(II) concentrations up to 1.44 nmol L−1 were observed at water depths below the euphotic zone, but above the oxic anoxic interface. Finally, all Fe(III) is reduced to Fe(II) in anoxic deep water. However, only a fraction thereof is present as ferrous ions (up to 28 nmol L−1) and was detected by the CL-FIA method applied. Despite their high concentrations, it is unlikely that ferrous ions originating from sub-oxic waters could be a temporary source of bioavailable iron to the euphotic zone since mixed layer depths after strong wind events are not deep enough in summer time.

scholarly journals Long-Term Mean Circulation of the Baltic Sea as Represented by Various Ocean Circulation Models

2018 ◽  
Vol 5 ◽  
Author(s):  
Manja Placke ◽  
H. E. Markus Meier ◽  
Ulf Gräwe ◽  
Thomas Neumann ◽  
Claudia Frauen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Ocean Circulation ◽  
The Baltic Sea ◽  
The Baltic ◽  
Mean Circulation
Sign in / Sign up

Export Citation Format

Share Document